The document discusses the basics of computer networks and the Internet. It defines a computer network as interconnected computers that allow sharing of resources like data and equipment. It then describes different types of networks including local area networks (LANs), metropolitan area networks (MANs), and wide area networks (WANs). The Internet is defined as a global system of interconnected computer networks that use TCP/IP protocols to share information worldwide. Common applications and services on the Internet like email, World Wide Web, and file transfer are also summarized.

1. THE INTERNET
Created by
s.kowsar

2. Computer network
• A computer network is a group of connected
computers so that they can share resources.
alternatively it is interconnection of computers
that allow people to share information and
equipment like printer and plotters etc
• Sharing a information : allow to people share data
and programs
• Sharing equipments : connected to a network can
share equipment such as printer plotters etc

3. Classification of networks
 Local Area Network (LAN)
 Metropolitan Area Network (MAN)
 Wide Area Networks (WAN)
 Internet
• Local Area Network (LAN): Privately-owned
networks
• Digital communication system capable of
interconnecting all computers
• Such as office , home etc
• LAN can communicate over twisted pairs, coaxial
or fiber optic cables.
• Using LAN we can share a peripherals like
printers and so an

4. continued
• Commincation speed range from 1
megabytes per second and 1 gigabyte
per second.
• Typical network consists a powerful
microcomputer having a large hard disk
known as network server
• It controls and communicate all other
network resources

5. Metroplatian area network(MAN)
• Depend on area covered by the
expanded network it s called
metropolitan or wide area network
• MAN are scattered around a
metropolitan area
• Cellular phone network area good
example of such network

6. Wide area networks• Widely separated by they may in different cities
,States or even countries
• Network of networks
• In WAN all LAN over a wide area are interconnected.
• The transmission medium used are normally public
systems such as telephone lines,microwave oe leased
lines and satelite links
• WAN communicates frequently take place over the
ordinary telephone system which

7. Wide Area Network(WANS)

8. Difference between LAN and WAN:
LAN WAN
ITS STANDA FOR LOCAL AREA NETWORK IT STANDS FOR WIDE AERA NETWORK
IT IS RISTRICTED TO A LIMITED
GEOGRAPHICAL OPERATW COUNTRY WIDE
OR EVEN WORLD WIDE
IT SPANS GREATER DISTANCE AND MAY
AERA,FROM 100 METERS TO ABOUT 10 KMS
COST OF DATA TRANMISSION IS VERY LOW COST OF DATA TRANMISSION IS VERT HIGH
COMPUTERS TERMINALS AND PERIPHERAL
DEVICES ARE PHYSICALLY CONNECTED WITH
WIRES AND COAXIAL CABLES
TH ECOMPUTERS TERMINALS AND
PERIPHERALS DEVICES MAY NOT BE
PHUSICALAY CONNECTED
DATA TRANSFER RATE IS HIGH DATA TRANSFOR RATE IS VERY LOW
DATA LOSS MAY NOT OCCUR DATA LOSS MAY OCCUR
LQANS ARE OWNED BY SINGLE
ORGANIZATION
WANS ARE OWNE DBY MANY
ORGANIZATIONS
ONLY LIMITED DATA CAN BE ACCESSED WORLD OF DATA CAN BE ACCESSED
COMMUNICATION LINKS ARE RELATIVELY
FAST
COMMINICATION CAN BE RELATIVELY SLOW

9. INTERNET
 LARGEST COMPUTER NETWORK
 IT CONNCEYS DIFFERENT TYPES OF COMPUTERS IN TE
WORLD
 IT IS CALLED NET
 IT LIKNS ONLY LANS BUT ALSO WANS
 INTERNETS IS THE NETWORK OF THE NETWORKS
• DEFINATION OF INTERNET
• The Internet is the global system of
interconnected computer networks that uses
the Internet protocol suite (TCP/IP) to
communicate between networks and devices.

10. Internet continued Interconnected physically
 Capable of commutating and sharing data
with each other
 Able to act together as a single network

11. Structure of internet
It connect a system all over the world
• All the computes are the same data and
timings formats know as networking
protocol.
 User system not connect directly to the
internet
 It is connected to the internet service
provider
 Computer called server.
 Which provided internet access the

12. Structure of internet
 ISP computer from different areas are
connected to a network that links other
network through a network are called back
done
Inter connections are called gateways between
these back done makes it possible for a
computer on one network to exchange
messages and data with another computer
connected to any other network

13. • Internet is a system connecting
computers around the world
using TCP/IP, which stands
for Transmission Control
Protocol/Internet Protocol, a
set of standards for
transmitting and receiving
digital data.

14. Applications of Internet
• Communication
Yahoomail.com, Hotmail.com,
Rediffmail.com
• Job searches
Naukri.com, monster.com,
Summerjob.Com,
recuritmentindia.com
•Finding books and study
material Latest

15. • Travels
Indiatravellog.com,
rajtravel.com,
makemytrip.com
• Entertainment
Cricinfo.com, movies.com,
espn.com
• Shopping
•Stock market updates
Ndtvprofit.com,
moneypore.com

16. Internet applications
See a daily news paper and magazines
Making friends in any part of the world using face
book etc
Visit a electronic zoo or a museum
Provide communication through E-Mail
Provides many services such as online banking , job
seeking and application and hotel reservation etc
To buy or sell products using e commerce

17. Internet services
• Internet services support thousand s
kinds of operational and experimental
services
• A few of the most popular include the
following Like
• E-mail
• www
• Gopher
• ftp

18. World Wide Web
• Open source information space
• Web resources – URLs,
interlinked by hypertext links
• Collection of internet resources
• Invented by English Scientist Tim
Berners – Lee in 1989
• First web browser – 1990
• Web pages – HTML

19. www
 World wide web is a service in the internet. Simply it is
defined a universal data base of knowledge
 www web is an application that uses the internet as a
platform.
 It communicates with any other the www is a global
application.
 It provides users with simply meaning of navigation and
selecting the huge volume of information available on
internet
 Information can form in a pages
 Pages are like the page of book with one difference one
page can take you to another entirely in different page
 It can retrieve from a server and displayed in a window.

20. continued
 It can display in a word processor.
 Certain pages on the page are distinguished as a hot
text either displaying in a different colour , or by
underlining them.
 Hot text is a known as hypertext link
 Clicking on results in the bringing up of a new page
of information in the users window
 It can be decode the information for client
 This page may be anywhere in world
 It can be use full in different environment
 Word processor files have extension like doc where
web documents like have a .HTML extension
 It contain pictures ,videos , graphics and so on
 It can be expandable both in terms of users and
facilities that its provides

21. Continued
 The separation of www into clients and server
components means it is every straight forward to
add extra clients and servers to the system
 Client and server can negative the document type that
they will use
 Server offer page based on a standard page
description language but can also provide proprietary
format such as Microsoft word
 Client software that allows a user access from
virtually any type of terminal pc is known as web
browser
 It os available from a number of different types like
google crome, firefox ,netscape ,inernet explorar and
so on

22. Purpose of www
 We can download the desired files available on other
computers in the internet you can upload for the interesting
documents
 Authorities can display the examination results on the web
such that all people in the world can view it
 You can do shopping from home
 You can listen audio view the movies etc

23. Terms in www• Hyperlink
• a connection that allows you to move easily between
two computer documents or two pages on the internet .
• Hyperyext:
• Webpages that have hyperlinks to other pages
• Browser:a browser is a software application used to locate,
retrieve and display content on the World Wide Web,
including webpages, images, video and other files. As a
client/server model, the browser is the client run on a
computer or mobile device that contacts the Web server
and requests information.

24. continued
• Clients and servers:
• A web server is a computer connected to the internet that
runs a program it is called web server
 It takes possibility of storing retrieving and distributing
some of the web files.
 Web browser is a computer that requests files from the
web.
 when a client computer wants access to one of the file on
the web the network directs to the web server that is
possible for that file.
 The server can retrives the file from its storage media and
sends it to the client computer that request it.

25. continued
• Web page:
 A web page is an HTML document that is stored on a web
server and that has a URL so that is can be accessed via the
web.
 It includes like text movie clips , animation videos ,and
pictures and so on.
• Website:
 It is an collection of web pages belongings to a particular
subject or person or organization
 It can accessed by typing the address of the website
• Web server:
 A web server is a computer connected to the internet that
runs a program that takes responsibility for storing
,retrieving and distributing some of the web files

26. continued
• HTML
I. It stands for hypertext markup language
II. It is a universal language of the web
III. This language can use to layout pages that are capable of
displaying all the devise kinds of information that the
web contain
• Protocal:
 Specified rules that enable computer to exchange
information
 It is a part of internet address the colon such ad
http,ftp,mail

27. Continued
• Search engines:
• a program that searches for and identifies items in a
database that correspond to keywords or characters
specified by the user, used especially for finding particular
sites on the World Wide Web
• Links:
• Web page usually contain links, which are highlighted text
or images on a web page that connect to other pages on the
pages. you can select a link to display a web page located
on the same computer or on a computer across the city,
country or worlds

28. gopher
• It is an interface that allows you to
create and use of directories of files
held on computers on the internet
,and builds link across the internet
in a manner that allows users to
browse through the files.

29. FTP
 FTP known as FILE TRANFER PROTOCOL
 it enables computer to speak to one another
 transfer a file over the internet
 Distribute a files to a number of users
 It is designed for communicating files between
individuals
 FTP uses a client-server system in which files are
stored as a central computer and transferred between
the computer and other widely distributed computers
 The central computer run software called an FTP
server
 The software at the other widely distributed computer
runs software called an FTP clients

30. continued
 The client request that a file transform be initiated
and the client and server exchange a data
 FTP communicates is always between clients and
servers, never between clients
 One person might send a file to a server and the other
person might then download that file but a server
must still be in the middle

31. email
• Email is known as electronic mail
• It is nothing but a portal services all the all the
way through computers
• Writing a letter through internet is known as
email
• It provides fast, economical and convenient
way to exchange messages with families
friends and so on
• You can send the message many people
• Cost are very low in mail once the user in
network
• We can also share alike text,database,videos
pictures and soon

32. continued
• If we send the mail to someone you need their unique
• e-mail address
• You can receive email when its send to your e-mail
address
• Email are passed through the internet by using a
protocol called Mail Transfer Protocol(SMTP).

33. Understanding E-mail address
 Send a messages in email user have a valid email id
 It defines the location of an individuals mail box on
the internet
 It consist of two parts like user’s name and the
domain name.
 These two are separated by @ symbol
 It cannot contain spaces
 Username is the name of the persons account and can
be a real name or a nick name
 Host or domain names is the location of the persons
account on the internet
 Periods (.) are separated the various parts of the
domain name.
 Host or domain name provide the internet location of
the mailbox , usually the name owned by a company
or internet service

34. continued• Example
• server name
• vmcknl@yahoomail.com
•
• username domain name
• Basic structure of email address is
username@organization.organazation.type.country for
example consider the following E-mail address like
• prasad@md.vsnl.net.in.
• Prasad-username
• Md-the server of vsnl
• Net -network operator
• In- india

35. Advantages of internet
• CONVIENCE : There Are No Trips To Post Office And
No Need To Search For Stationary Like Stamps , Sending
Memos Or Short Note Is Easy.
• E-mail Makes Publishing And Discussing Very Easy.
• SPEED : It Is Fast, Based On Speed Of The Network
• INEXPENSIVE : Once U Are In Online The Cost Of
Sending A Message Of A Message
• PRINTABLE : Hardcopy Is Easy To Obtain. Keep An
Electronic Copy Of A Message For Your Own Records
• GLOBAL :people And Business All Over The World Are
Using E-mail.
• GENERALLY : e-mail is not limited to test , it allows the
transfer of graphics, programs even sounds.

36. Web browsers
• Web browsers: a web browser is a program used to
search the internet and display the web data
 Web browser is a program the your computer runs to
communicate with web servers on the internet,
 Which enables to download and display the web
pages that you request
 It has ability to display so many types of files
 You often ,ay use a web browser even when you
aren’t connected to internet.

37. INTERNET ADDRESSING
 Internet addressing system is used to keep track of
millions of its users
 Each computer on the network is called a HOST and
has a name and a number
 Id is used for identify people computers and internet
resources
 It can be identify by IP address and domain name
 People can be identified by email address
 Resources and files available through the web are
identified using URLS

38. Continued
• Internet address codes
Domain description
com
Edu
Org
Gov
Mil
Net
int
Commercial organizations as well as
individuals
Education
Network that are involved in providing
network
Government agencies
Military
Internet service providers and other
network relates companies
international organizations like
who,uno etc

39. continued
• Some domain are organized by country using two
chartecres national identification code .
Domain name Description
In India
Za South Africa
Us United states
Nz New Zealand
Uk United kingdom
De Germany
Ca Canada
Se Sweden
Fr France
Jp Japan

40. Starting outlook express
• You can start outlook express to exchange e-mail
message with people around the world
• Now double click on the outlook express on your
desktop
• The outlook express window appears
• If you are not currently connected to the internet to
the inetrnet ,the connect dialogue box also appears
• Type user name and password and then click connect

42. continued
Folder name Description
Inbox Stores messages to you
Outbox Temporarily stores messages that
have not yet been sent
Sent items Stories copies of messages you have
sent
Deleted items Stores messages you have deleted
Drafts stores messages you have not yet
completed

43. Reading an E-mail message
• You can easily open your messages to read their
contents
• If the mail download s your messages or after click
the send/recv button on the toolbar, you can read
messages either in a separate windows or in the
preview pane
1. Click the inbox icon
2. To view the messages in the preview pane , click the
messages in the messages list
3. To view the messages in a separate window ,double
click the messages in the messages list

44. Sending an email messages
• On the tool bar click the compose button
• In that TO or Cc boxes will open the the mail name
and each receipt separating names with a comma or
semicolon
• To:send the messages to each person you specify
• In the subject box,type a messages title
• Type your messages and then click the send button
on the new message toolbar
• The new message window will appears

45. INTERNET SERVICE PROVIDER(ISP)
• An ISP provides that provides internet facility
• In order to connect to the internet by using dialup phone ,
high speed line or leased lines , you first need to choose an
ISP
• It assign a telephone number username password so that
you can connect your computer to the ISP’S computers
• One computer can connect to the internet by using a
network connection or an ISP .
• Once you connect to the system, you have access to the
internet and all other services provided by your ISP
• ISP’S basically provides two types of connections one is
shell account which is cheapest and the other is ICP/IP
• account

46. continued
• In shell account all necessary software is available
with ISP and you are able to work with only text-
based information
• In TCP/IP account ISP does not provide the necessary
software to work and connect to the internet.
• Here you able to work with all types of information
including colorful graphics ,sounds , motions pictures
etc.
• In india one can get internet connection from the
following organizations(ISP’S)
 VSNL (videsh sanchar nigam limited)which is a
governament organization
 MTNL (mahanagar telephone nigam limited)which
can be a governament organization

47. Continued
 Some of private ISP’S
 Satyam on line
 Nettlink online
 Pioneer online
 Global online

48. Starting an internet explorar
• To connect to internet to perform several steps like
• Double click on the internet explorer icon your desktop.
The internet explorer windows appears on your screen.
• Type in search as you wish and click enter
• It will open in same page then you can open any link
which can be display displayed in in front of us

49. Role of a modem in internet
 MODEM STANDS FOR MOduler / DEModuler
 It is connected between a computer and telephone
lines and vice-versa
 When two computers are communicate with each
other , they cannot interpret the analog data come over
telephone lines
 So modem works as a translator between computer
and telephone lines and vice-versa
 It translates digital signal from the computer at the
sending end to analog signals that can pass over the
telephone lines
 At the receiving end , another modem translates the
analog signals back the digital signals can be used by
the computers.

50. continued
 The conversion from digital or binary to analog is called
modulation and the conversion back from analog to digital
is called demodulation
 The speed at which modems trasmot data is called the
throughput. This is measured in bits per seconds(bps)

51. Technical terms
• Bit: The smallest piece of data that can be recognizes and
used by the computer is the bit , a binary digit . either a zero
or a one
• Byte: a group of eight bite is called a byte . a byte can
represent any character . it is the basic unit for measuring the
size of memory.
• Word : a group of bits represents data or an instruction that
form the basic information.
• GB=1024 MB
• TB=1024 GB